Vibrio cholerae is the causative agent of cholera, a disease characterized by severe diarrhea and dehydration. As a natural inhabitant of oceans, estuaries, rivers, and lakes, V. cholerae is well adapted for survival in both fresh water and marine environments. V. cholerae bioflims have been observed in the human intestine and in the aquatic environment. The goal of this research is to identify and characterize the genes and environmental signals that guide bio film development by V. cholerae in diverse aquatic environments. Results of this work may provide a scientific basis for the correlation of epidemic cholera with environmental parameters, increase our understanding of the diversity of bioflims formed by gram-negative organisms, and form the basis for rational design of inhibitors of bacterial attachment to be used in environmental approaches to the control of cholera and in the prevention of biofilm-associated infections including central venous catheter sepsis, prosthetic joint infections, and endocarditis. The Specific Aims of this research are: 1) To study the mechanism of action of Bfr 1, a recently identified, novel regulator of biofilm development, 2) To identify and characterize additional environmental signals and regulators that guide V. cholerae biofilm development in fresh water, and 3) To identify and characterize the environmental signals and regulators that guide V. cholerae biofilm development in sea water.